mu/src/mu-msg-iter.cc

/*
** Copyright (C) 2008-2011 Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
**
** This program is free software; you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation; either version 3 of the License, or
** (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
** GNU General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with this program; if not, write to the Free Software Foundation,
** Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
**
*/

#include <stdlib.h>
#include <iostream>
#include <string.h>
#include <errno.h>
#include <xapian.h>

#include "mu-util.h"
#include "mu-msg-iter.h"
#include "mu-msg-iter-priv.hh"

struct _MuMsgIter {

	_MuMsgIter (const Xapian::Enquire &enq, size_t batchsize):
		_enq(enq), _batchsize(batchsize), _offset(0) {

		_matches = _enq.get_mset (0, _batchsize);
		_cursor	 = _matches.begin();
		_is_null = _matches.empty();
		clear_fields (false);
	}

	~_MuMsgIter () {
		clear_fields (true);
	}

	void clear_fields (bool dofree) {
		for (int i = 0; i != MU_MSG_FIELD_ID_NUM; ++i) {
			if (dofree)
				g_free(_str[i]);
			_str[i] = NULL;
		}
	}
	
	const Xapian::Enquire          _enq;
	Xapian::MSet                   _matches;
	Xapian::MSet::const_iterator   _cursor;
	size_t                         _batchsize, _offset;
	char*                          _str[MU_MSG_FIELD_ID_NUM];
	bool                           _is_null;
	
	
};



MuMsgIter*
mu_msg_iter_new (const Xapian::Enquire& enq, size_t batchsize)
{
	try {
		return new MuMsgIter (enq, batchsize);
		
	} MU_XAPIAN_CATCH_BLOCK_RETURN(NULL);
}


void
mu_msg_iter_destroy (MuMsgIter *iter)
{
	try { delete iter; } MU_XAPIAN_CATCH_BLOCK;
}


MuMsg*
mu_msg_iter_get_msg (MuMsgIter *iter, GError **err)
{
	const char *path;
	MuMsg *msg;
	
	g_return_val_if_fail (iter, NULL);
	g_return_val_if_fail (!mu_msg_iter_is_done(iter), NULL);
	
	path = mu_msg_iter_get_path (iter);
	if (!path) {
		g_set_error (err, 0, MU_ERROR_XAPIAN_MISSING_DATA,
			     "no path for message");
		return NULL;
	}

	msg = mu_msg_new_from_file (path, NULL, err);
	if (!msg) 
		return NULL;

	return msg;
}


static gboolean
message_is_readable (MuMsgIter *iter)
{
	Xapian::Document doc (iter->_cursor.get_document());
	const std::string path(doc.get_value(MU_MSG_FIELD_ID_PATH));
	
	if (access (path.c_str(), R_OK) != 0) {
		g_debug ("cannot read %s: %s", path.c_str(),
			 strerror(errno));
		return FALSE;
	}

	return TRUE;
}
		
static MuMsgIter*
get_next_batch (MuMsgIter *iter)
{	
	iter->_matches = iter->_enq.get_mset (iter->_offset, iter->_batchsize);
	if (iter->_matches.empty()) {
		iter->_cursor = iter->_matches.end();
		iter->_is_null = true;
	} else {
		iter->_cursor = iter->_matches.begin();
		iter->_is_null = false;
	}
		
	return iter;
}

gboolean
mu_msg_iter_next (MuMsgIter *iter)
{
	g_return_val_if_fail (iter, FALSE);

	if (mu_msg_iter_is_done(iter))
		return FALSE;
	
	try {
		++iter->_offset;
		if (++iter->_cursor == iter->_matches.end())
			iter = get_next_batch (iter);
		if (iter->_cursor == iter->_matches.end())
			return FALSE; /* no more matches */
		
		/* the message may not be readable / existing, e.g.,
		 * because of the database not being fully up to
		 * date. in that case, we ignore the message. it
		 * might be nice to auto-delete these messages from
		 * the db, but that might screw up the search;
		 * also, we only have read-only access to the db
		 * here */
		/* TODO: only mark it as such, let clients handle
		 * it */
		if (!message_is_readable (iter))
			return mu_msg_iter_next (iter);
		
		iter->clear_fields (true);

		return TRUE;
		
	} MU_XAPIAN_CATCH_BLOCK_RETURN(FALSE);
}


gboolean
mu_msg_iter_is_done (MuMsgIter *iter)
{
	return iter ? iter->_is_null : TRUE;
}


static const gchar*
get_field (MuMsgIter *iter, MuMsgFieldId mfid)
{
	if (!iter->_str[mfid]) { /* cache the value */
		try {
			const std::string s
				(iter->_cursor.get_document().get_value(mfid));
			iter->_str[mfid] = s.empty() ? NULL : g_strdup (s.c_str());
			
		} MU_XAPIAN_CATCH_BLOCK_RETURN(NULL);
	}
	return iter->_str[mfid];
}

const gchar*
mu_msg_iter_get_field (MuMsgIter *iter, MuMsgFieldId mfid)
{
	g_return_val_if_fail (!mu_msg_iter_is_done(iter), NULL);
	g_return_val_if_fail (mu_msg_field_id_is_valid(mfid), NULL);

	return get_field (iter, mfid);
}




static gint64
get_field_numeric (MuMsgIter *iter, MuMsgFieldId mfid)
{
	const char* str;

	str = get_field (iter, mfid);
	if (!str)
		return 0;
	
	try {
		return static_cast<gint64>(Xapian::sortable_unserialise(str));

	} MU_XAPIAN_CATCH_BLOCK_RETURN(static_cast<gint64>(-1));
}


gint64
mu_msg_iter_get_field_numeric (MuMsgIter *iter, MuMsgFieldId mfid)
{
	g_return_val_if_fail (!mu_msg_iter_is_done(iter), -1);	
	g_return_val_if_fail (mu_msg_field_is_numeric(mfid), -1);
	
	return get_field_numeric (iter, mfid);
}


unsigned int
mu_msg_iter_get_index (MuMsgIter *iter)
{
	g_return_val_if_fail (iter, (unsigned int)-1);

	return iter->_offset;
}


/* hmmm.... is it impossible to get a 0 docid, or just very improbable? */
unsigned int
mu_msg_iter_get_docid (MuMsgIter *iter)
{
	g_return_val_if_fail (!mu_msg_iter_is_done(iter),
			      (unsigned int)-1);	
	try {
		return iter->_cursor.get_document().get_docid();

	} MU_XAPIAN_CATCH_BLOCK_RETURN (0);
}


const char*
mu_msg_iter_get_path (MuMsgIter *iter)
{
	g_return_val_if_fail (!mu_msg_iter_is_done(iter), NULL);
	return get_field (iter, MU_MSG_FIELD_ID_PATH);
}

const char*
mu_msg_iter_get_maildir (MuMsgIter *iter)
{
	g_return_val_if_fail (!mu_msg_iter_is_done(iter), NULL);
	return get_field (iter, MU_MSG_FIELD_ID_MAILDIR);
}

const char*
mu_msg_iter_get_msgid (MuMsgIter *iter)
{
	g_return_val_if_fail (!mu_msg_iter_is_done(iter), NULL);
	return get_field (iter, MU_MSG_FIELD_ID_MSGID);
}

const char*
mu_msg_iter_get_from (MuMsgIter *iter)
{
	g_return_val_if_fail (!mu_msg_iter_is_done(iter), NULL);
	return get_field (iter, MU_MSG_FIELD_ID_FROM);
}

const char*
mu_msg_iter_get_to (MuMsgIter *iter)
{
	g_return_val_if_fail (!mu_msg_iter_is_done(iter), NULL);
	return get_field (iter, MU_MSG_FIELD_ID_TO);
}


const char*
mu_msg_iter_get_cc (MuMsgIter *iter)
{
	g_return_val_if_fail (!mu_msg_iter_is_done(iter), NULL);
	return get_field (iter, MU_MSG_FIELD_ID_CC);
}

const char*
mu_msg_iter_get_bcc (MuMsgIter *iter)
{
	g_return_val_if_fail (!mu_msg_iter_is_done(iter), NULL);
	return get_field (iter, MU_MSG_FIELD_ID_BCC);
}


const char*
mu_msg_iter_get_refs (MuMsgIter *iter)
{
	g_return_val_if_fail (!mu_msg_iter_is_done(iter), NULL);
	return get_field (iter, MU_MSG_FIELD_ID_REFS);
}

const char*
mu_msg_iter_get_subject (MuMsgIter *iter)
{
	g_return_val_if_fail (!mu_msg_iter_is_done(iter), NULL);
	return get_field (iter, MU_MSG_FIELD_ID_SUBJECT);
}


size_t
mu_msg_iter_get_size (MuMsgIter *iter)
{
	g_return_val_if_fail (!mu_msg_iter_is_done(iter), 0);
	return static_cast<size_t>(
			get_field_numeric (iter,MU_MSG_FIELD_ID_SIZE));
} 


time_t
mu_msg_iter_get_date (MuMsgIter *iter)
{
	g_return_val_if_fail (!mu_msg_iter_is_done(iter), 0);
	return static_cast<time_t>(
			get_field_numeric (iter,MU_MSG_FIELD_ID_DATE));
}

MuMsgFlags
mu_msg_iter_get_flags (MuMsgIter *iter)
{
	g_return_val_if_fail (!mu_msg_iter_is_done(iter), MU_MSG_FLAG_NONE);
	return static_cast<MuMsgFlags>(get_field_numeric
				       (iter, MU_MSG_FIELD_ID_FLAGS));
} 

MuMsgPrio
mu_msg_iter_get_prio (MuMsgIter *iter)
{
	g_return_val_if_fail (!mu_msg_iter_is_done(iter),
			      MU_MSG_PRIO_NONE);
	return static_cast<MuMsgPrio>(get_field_numeric
				      (iter, MU_MSG_FIELD_ID_PRIO));
}